The improvement of cardiac multispiral computed tomography protocol for planning interventional arrhythmia management

Purpose. The study aimed at the comparison of computed tomography (СT) contrast enhancement (CE) protocols for optimal visualization of cardiac chambers, evaluation of their impact on results of non-invasive superficial cardiac mapping.Methods. The study included 93 patients with heart rhythm disorders in whom catheter ablation of arrhythmia was planned. Noninvasive cardiac mapping for arrhythmia localization was performed and included multichannel ECG-registration and CT with intravenous СE (1st group - monophasic (50 patients), 2nd group - split-bolus (18 patients), 3rd group - with pre-bolus (25 patients). Qualitative and quantitative (measurement of mean blood attenuation in four chambers, calculation of ventricular-myocardial [VM] contrast-to-noise ratio VM-LV и VM-RV for the left ventricle [LV] and right ventricle [RV], respectively) parameters were compared between the groups. Fusion of ECG and CT data was carried out a semi-automatic mode with a non-invasive imaging complex.Results. Regardless of CE technique, sufficient and homogeneous contrast attenuation was obtained for the left atrium (LA) and LV (mean blood attenuation in LA more than 278 HU, LV 250 HU, VM-LV 0,582). In most cases, the enhancement of the right heart was insufficient with the monophasic protocol; the average CT density was lower than 200 HU, VM-RV 0,256. The split-bolus protocol improved visualization of the right atrium (RA) and RV (blood density in RA 258HU, RV 227HU, VMRV 0,541); however, there was a heterogeneity of the RA cavity due to artifacts from the superior vena cava (VC) and unenhanced blood from the inferior VC. Pre-bolus administration increased the contrast ratio between RA myocardium and blood due to the improvement of blood CT density in the inferior VC (blood density 294 HU). The quality of RV CE was similar to 2nd group (blood density 264 HU, VM-RV 0,565).Conclusion. The split-bolus and with pre-bolus CE protocols improve visualization of the RV, supporting the high-level enhancement of the left heart. The protocol with a pre-bolus is preferable for exact differentiation of the right atrial endocardial contour.

The improvement of cardiac multispiral computed tomography protocol for planning interventional arrhythmia management

Purpose. Comparison of computer tomography (СT) contrast enhancement (CE) protocols for optimal visualization of cardiac chamber, definition it’s influence on results of non-invasive superficial cardiac mapping.Materials and methods. The study included 93 patients with heart rhythm disorders who planned catheter ablation of arrhythmia. Noninvasive cardiac mapping was made for topical diagnostics. It includes multichannel ECG-registration and CT with intravenous СE (1st group monophasic (50 patients), 2nd group split-bolus (18 patients), 3rd group with pre-bolus (25 patients). Qualitative and quantitative (measurement of mean blood attenuation in four chambers, calculation of ventricular-myocardial contrast-to-noise ratio VM-LV и VM-RV for left ventricle (LV) and right ventricle (RV), respectively) parameters were compared between groups. Fusion of ECG and CT data was made semi-automatic with diagnostic complex «Amycard 01К».Results. Regardless of CE technique was noted sufficient and homogeneous contrast attenuation of left atrium (LA) and LV (mean blood attenuation in LA more than 278 HU, LV 250 HU, VM-LV 0,582). Enhancement of right heart was insufficient with monophasic protocol, in most cases the average CT density was lower than 200 HU, VM-RV 0,256. Split-bolus protocol improves visualization of right atrium (RA) and RV (blood density in RA 258HU, RV 227HU, VM-RV 0,541), however there was heterogeneity of RA cavity because of artifacts from superior vena cava (VC) and unenhanced blood from inferior inferior VC. Using of pre-bolus increases contrast ratio between RA myocardium and blood due to increasing CT density of blood in inferior VC (blood density 294 HU). Quality of right ventricle CE was similar to 2nd group (blood density 264 HU, VM-RV 0,565).Conclusion. CE protocols split-bolus and with pre-bolus improve visualization of right ventricle, supporting the high level enhancement of left heart. Protocol with pre-bolus is preferable for exact differentiation of right atrial endocardial contour.

P737 Left ventricular hemodynamic forces: towards establishing reference values for healthy adults

Introduction Left ventricular hemodynamic forces (LV-HDF) have been recently demonstrated to be promising markers of sub-clinical dysfunction and potential predictors of disease outcome. However, there is a lack of reference values in healthy subjects. Knowledge of physiologic ranges is mandatory towards the use of LV-HDF-based indices for disease assessment in future clinical applications. Purpose Aim of the current study is to define the normal reference values for LV-HDF parameters in a large cohort of healthy adults. Here we present preliminary results for the initial set of enrolled subjects. Methods We enrolled 82 healthy subjects [mean age 44 ± 13.2 years (range 18-88), 41 men]. All participants underwent standard transthoracic echocardiography (TTE) examination, as recommended by current guidelines, including apical two-, three- and four-chamber windows, acquired at a frame rate above 40 Hz. These were then analyzed by tri-plane tissue tracking, measuring LV volume and LV ejection fraction (EF) as reference parameters. The same tracking method was used to evaluate the global hemodynamic force by a novel mathematical calculation technique applied to the three-dimensional endocardial contour. Physical-based LV-HDF parameters were then extracted for clinical application; these included the amplitude (root mean square) of the longitudinal and transversal force components (FL and FT) and their alignment angle relative to the LV axis. Parameters were computed as average over the whole cardiac cycle as well as limited to the systolic phase. Forces were normalized with LV volume to reduce variability with LV dimension, and divided by specific weight to yield a dimensionless measure. Results Mean EF was 63 ± 9%. Whole cycle LV-HDF parameters were: FL = 16.0 ± 5.6%, FT = 2.3 ± 0.8%, with significant longitudinal alignment FT/FL = 0.15 ± 0.04, angle = 13.0°±3.1°. Systolic HDF parameters were: FL = 22.7 ± 8.2%, FT = 2.9 ± 1.1%, with longitudinal alignment FT/FL = 0.13 ± 0.04, angle = 11.2°±3.1°. Importantly, dimensionless physical-based LV-HDF parameters showed no significant variation with age, gender or BSA. Conclusions We report the physiologic range of LV-HDF parameters measured by TTE. Knowledge of age- and gender-specific reference values, for a combination of standard, mechanical and hemodynamic indices, can improve the global assessment of the LV function and may help to detect sub-clinical stages of LV dysfunction.

Assessment of right ventricular geometry and function from real time three-dimensional echocardiography in patients with acute decompensated heart failure and implanted intracardiac devices

This study was designed to compare two methods for quantifying right ventricular (RV) geometry and function obtained from real-time three-dimensional echocardiography in patients with acute decompensated heart failure and implanted intracardiac devices. 42 patients (29 men and 13 women) aged 29 to 78 years with acute heart failure were included into the research. Three-dimensional reconstruction RT-4DE Tom Tec revealed several advantages in determining the volume and right ventricular function in comparison with 4-D LV Echo PAC program in cases of complicated geometry of endocardial contour of the right ventricle.

A Hybrid Method for Endocardial Contour Extraction of Right Ventricle in 4-Slices from 3D Echocardiography Dataset

This paper presents a hybrid method to extract endocardial contour of the right ventricular (RV) in 4-slices from 3D echocardiography dataset. The overall framework comprises four processing phases. In Phase I, the region of interest (ROI) is identified by estimating the cavity boundary. Speckle noise reduction and contrast enhancement were implemented in Phase II as preprocessing tasks. In Phase III, the RV cavity region was segmented by generating intensity threshold which was used for once for all frames. Finally, Phase IV is proposed to extract the RV endocardial contour in a complete cardiac cycle using a combination of shape-based contour detection and improved radial search algorithm. The proposed method was applied to 16 datasets of 3D echocardiography encompassing the RV in long-axis view. The accuracy of experimental results obtained by the proposed method was evaluated qualitatively and quantitatively. It has been done by comparing the segmentation results of RV cavity based on endocardial contour extraction with the ground truth. The comparative analysis results show that the proposed method performs efficiently in all datasets with overall performance of 95% and the root mean square distances (RMSD) measure in terms of mean ± SD was found to be 2.21 ± 0.35 mm for RV endocardial contours.

LV Challenge LKEB Contribution: Fully Automated Myocardial Contour Detection

In this paper a contour detection method is described and evaluated on the evaluation data sets of the Cardiac MR Left Ventricle Segmentation Challenge as part of MICCAI 2009’s 3D Segmentation Challenge for Clinical Applications. The proposed method, using 2D AAM and 3D ASM, performs a fully automated detection of the myocardial contours, not requiring any user interaction. The algorithm’s performance is reported using the metrics provided by the LV Challenge organization. Endocardial contour detection was classified as successful in 86% of the images and epicardial contours in 94%. The average perpendicular distance (APD) of the successful contours was 2.28 mm and 2.29 mm for the endo- and epicardial contours, respectively.